Dodge Neon over heating

DODGE NEON

DAVE BUCKLEY

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4 POSTS
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I have a 1997 neon 2.0 DOHC,115000 miles. the car has been overheating and we can't ssem to find a problem. Took it to a garage and they replaced the radiator and cap, told us to try it to see waht happens. It still over heats, the garage say's they can't find anything wrong but feel's it's a head gasket. Before replacing the head gasket we took it to another shop. The coolent system was completely checked over, pressure tested at 30psi and holds for over 3 min. replaced the thermostat again, upper and lower radiator hoses. can not find any causes for it to over heat, fans run no fluid in the oil or cylinders. was not putting out heat until the termostat was changed for the second time. No codes in the computer. Should we replace the head gasket, or did they miss something? We are at a loss with this one because it shows no reason to keep overheating
Thanks

Dec 9, 2006 at 7:24 AM

MATHIASO

CERTIFIED EXPERT
1,209 POSTS

There are several reasons why the coolant in an engine may become too hot:
you have changed the thermostat,radiator and radiator cap.They should have been tested before any replacement took place.that 's what we call a needle in the dark.
now let me say this:

-A correctly sealed cooling system will maintain it for 15 minutes to the specified level, and not 3 minutes

Ask your mecanic to check the cylinder head gasket:
tell him to leave the cooling system pressure tester connected the radiator filler neck an apply a low pressure of aproximately 5 psi. run the engine at idle while observing the gauge.
execessive pressure buildup indicates combustion chamber pressure are intering the cooling system.
then you have to change the head gasket.

Dec 9, 2006 at 10:18 AM

DAVE BUCKLEY

MEMBER
4 POSTS

Ok, I had this done today. No problems with the pressure test. It held for 30 min. No rapid increase in pressure when it was started, did not bouce when it was warmed up and pressure arrived at normal temp. (from what I was told)
Is it possible that the coolent sensor or fan realy is bad and where are those located on this system?

Dec 11, 2006 at 4:40 PM

ALYOURSELF

MEMBER
3 POSTS

I just helped a friend of mine with his 95 and it was the coolant temp sensor. I cant remember what he paid but the part was fairly cheap at Autozone. Do you hear your fan kicking on? Let it sit and run for awhile on the driveway and see if the fan kicks on.

Dec 14, 2006 at 9:08 PM

MATHIASO

CERTIFIED EXPERT
1,209 POSTS

- if an air dam is damage, your fan may not really directing enough air up into the radiator.

let me know

mathiaso

Dec 15, 2006 at 7:19 AM

DAVE BUCKLEY

MEMBER
4 POSTS

Ok, change the thermostat, changed the Temp Sensor. Seemed fine, ran for over an hour in the driveway, fans run, no issues. Drove it over the weekend about a 45 min drive and it overheated. Checked for PCM Codes, none. Fans were running, no heat. Wondering if there is a intermitent blockeage some where in the heater line/core? Dealear told me that the PCM or Fan relay could be failing and giving intermitent faults. I'm looking at over 500$ in parts to guess on a possible eletrical issue?? When it got hot we shut it down and the fans quit running had to turn it back on for the fans to run. Checked the coolent and the level was still good, hoses hot, however the hoses to the heater core were cool, including the line from the thermostat housing?? I am puzzeled!

Dec 18, 2006 at 10:02 AM

MATHIASO

CERTIFIED EXPERT
1,209 POSTS

if you suspect there is a blockage in the internal passages of the engine,you can take care of that by reverse-flushing the block with water and air pressure.
a- attach the flush gun adapter to the uper hose of the radiatorand turn on the compressed air in short blast.

Dec 20, 2006 at 11:08 AM

MATHIASO

CERTIFIED EXPERT
1,209 POSTS

By the way I have to tell you that Certain ignintion system problem can cause engine overheating. check your ignition timing,because the aire and fuel misture in the cylinder could burn at the wrong time causing the negine to run at higherthan normal.

please check this one and let me know.

mathiaso

Dec 20, 2006 at 11:19 AM

DAVE BUCKLEY

MEMBER
4 POSTS

Ok, went to the next step and replaced the head gasket, had the head checked and rebuilt. reset everything including the timing and if fired right up. Let it run for about 30 min. and it started to everheat again and still had no flow in the heater lines. Water pump was replaced over the summer along with the timing belt, resurfaced the head, new valves, springs and seals, new radiator, hoses, temp sensor, and thermostat. Fans run, with it in defrost mode the fans run more often like they should but no heat. I removed the upper heater core line and had VERY little flow coming from the block or the hose, this was while it was running also. After almost 900$ i'm still in the same boat. I have no idea what to do next. I don't feel that it is caused by the heater core because there is no flow to it.

Jan 5, 2007 at 4:59 PM